Hot top for the casting of molten metals



G. R. WlTT HOT TOP FOR THE CASTING OF MOLTEN METALS Filed Jan. 29. 1962Dec. 29, 1964 United States Patent 3,162,913 HOT TOP FOR THE CASTING OF-MOLTEN METALS George R. Witt, Avon Lake, Ohio, assignor to FosecoInternational Limited, Birmingham, England, a company of Great BritainFiled Jan. 29, 1962, Ser. No. 169,216 3 Claims. (Cl. 22-147) Thisinvention relates to the casting of molten metals and more particularlyto the construction of hot tops, head boxes, and heads of molds used forthis purpose.

In the casting of molten metal in a mold to form an ingot or casting, aheat retaining lining, herein referred to as a hot top, is desirablyprovided at the head of the mold in order to conserve heat and keep anamount of metal molten so that it feeds the ingot or casting as itsolidifies. Such a hot top often comprises a liningor insert within themold, or in a head box attached to the mold, of sections of materialhaving a special function. For example, the sections may consist ofinsulating refractory material, in which case they serve to delaytransmission of heat away from the head metal and thus delay itssolidification. Alternatively, the sections may consist of a compositionof ingredients which interact exothermically when the composition isfiredby the heat of the molten metal. In the latter case a more positivedelay in the cooling of the head metal is achieved, which facilitatesfeed of the head metal to the body of the cast metal to compensate forthe shrinkage of that metal as it cools. 1

To secure such sections in position asa hot top in a mold, variousmethods have been proposed such as the the use of wooden Wedges, ormaking the sections in a shape so that they are self-wedging. It will beappreciated, however, that since the sections are usually located inposition by working above them, the wedges must be driven downwardly.When the molten metal rises in the mold and hot top, it exerts asubstantial upward thrust on the lining or insert and as a result maydislodge the wedges and lift the hot top upwardly.

It is a primary object of the present invention to provide a new andimproved form of hot top lining which is stronger, tighter fitting, andmore reliable than hot top constructions heretobefore employed.

Another object of the present invention is to provide a hot top liningof the foregoing character which is formed of individual sectionssuitable for mounting in a mold or head box, and which, when mounted inplace as a hot top is held tightly against the mold walls andsuccessfully resists the upward thrust of the molten metal being poured.

Still another object of the present invention is to provide a hot toplining of the foregoing character which rigidly abuts against the moldwalls to prevent leakage of molten metal between the lining and thewalls.

Another object of the invention is to provide an improved hot top formedof sections such as relatively flat shipped in compact form and bereadily and easily constructed into a hot top or mold lining in theplace where it is to be used.

Still a further object of the present invention is to provide animproved hot top construction and mounting which eliminates thenecessity of employing a stop-pour type of metal casting operation withthe resultant sub- 3,162,913 Patented Dec. 29, 1964 ice stantialelimination of leaking or running stoppers, and thereby improves theyield of ingots and reduces the waste of hot tops. I

Other objects and advantages of the present invention will becomeapparent as the following description pro ceeds taken in connection withthe accompanying drawings wherein:

FIGURE 1 is a plan view of a sectional hot top em bodying the presentinvention mounted in place in the mouth of an ingot mold.

FIG. 2 is a section view taken substantially in the plane of line 22 onFIG. 1.

FIG. 3 is a perspective view of a sectional hot top embodying thepresent invention in assembled condition just prior to mounting in aningot mold.

FIG. 4 illustrates a compression clip used when mounting a hot topembodying the invention in an ingot mold.

While certain illustrative embodiments of the invention have been shownin the drawings and will he described below in considerable detail, itshould be understood that there is no intention to limit the inventionto the specific forms disclosed. On the contrary, the intention is tocover all modifications, alternative constructions, equivalents, anduses falling within the spirit and scope of the invention as expressedin the appended claims.

Hot top linings embodying the present invention find particular but notnecessarily exclusive use with ingot molds. Such molds may be of anysuitable type presently in use in the steel industry. These molds may beprovided with a separate hot top casing (not shown) or the hot'toplining may be mounted directly on the mold or as an insert within themold cavity.

One illustrative form of the invention is shown in FIGS. 1-3 andcomprises a sectional sleeve shaped hot top lining or insert 10 mountedwithin the open mouth 11 of an ingot mold 12. It will be appreciated bythose skilled in the art that the hot tops embodying the presentinvention are equally applicable to many other types of molds such asslab molds, and the invention is not restricted in its applicability toonly molds of the type shown. In describing the invention, referencewill be made to slab-like sections or slabs, although the inventionshould not be restricted.

In accordance with the present invention, there is provided a strong,self-supporting hot top formed of four slabs including two end slabs 14and two side slabs 15 arranged to define a generally rectangular hot topsleeve. The individual slabs interlock one with another in a horizontaldirection to form the rectangular sleeve and prior to mounting in a moldare held together by pins 16 extending through holes 17 in theinterlocking portion of the slabs. In the interlocking hot top'shownforming this sleeve, the end and side slabs abut each other at thecorners of the sleeve and each slab interlocks with the adjacent slab.Such an interlocking slab arrangement is described and claimed incopending application Serial No. 150,478, filed November 6, 1961, andassigned to the assignee of the present invention, now abandoned. Theinterlocking arrangement between the slabs is provided by a horizontallyextending tongue 18 on one of the slabs which is received in a slot 19defined by a pair of spaced horizontally extending tongues 20, 21 on anadjacent slab as shown in FIG. 3. These tongues are constructed andarranged so as to fit closely together to prevent leakage of moltenmetal between them when the sleeve is formed. To this end, the tonguesmay taper slightly from a larger vertical width at a point adjacent theslab body to a slightly smaller width at the free end of the tongue.These tongues extend horizontally from each vertical side of the slabsso that, by making the length of each tongue, as measured horizontally,equal to the thickness of the slabs when the slabs are interlocked atright angles, they form a rectangular sleeve- Ipipe 31 extendingvertically through the slabs.

shaped hot top which is free from unwanted projecting surfaces ordepressions, and at the same time a tight, rigid, leakproof joint isprovided between the slabs.

For supporting the slabs'within the mouth of ingot mold, the two opposedside slabs 15 are provided in their upper edges, '-with upstanding ringsor hooks 24 which are engaged by a bar 25 extending between the corre*sponding walls of the ingot mold, and which rest on the upper ends 26 ofthese walls. The bar 25'serv'es to support the hot top It? within themold 12' and, because of the interlocking arrangement of the slabs 14,I5, the-sleeve 19' is securely supported with all of the slabs thereofin position adjacent the mold walls. 1

As shown in the drawings, the sleeve-shaped hot top lining 19 embodiyingthe invention is inserted within the open mouth of the mold 12 and whenmounted in place is held tightly therein with the slabs forming thesides of the lining tightly in engagement with the walls of the mold.Alternatively, the sleeve-shaped lining could be inserted in a permanenthot top casing. The method of mounting to be described will be the samewhether the lining is mounted directly in the mold or in the'hot topcasing.

For holding the slabs which form the side walls of the hot top intightlyjuxtaposed position againstthe mold walls, means are provided forexpanding the sleeve to urge the slabs apart and into contactwith themold walls. One illustrative means shown in the drawings comprises agenerally Ll-shaped hair-pin like expansion clip 26, having a pair ofdownwardly extending and; outwardly inclined legs 27, 23-positioned ateach corner of 'the As an alternative way of mounting the hot top sleevein a mold, which avoids the use of the corner pins 16,

the expansion clip holes in the ends of the slabs may also be utilizedto hold the slabs together and facilitate the insertion of the hot topsleeve into the mold. To this end, means are provided for engaging theholes and holding the slabs together. One illustrative means for thispurpose comprises a 'compression clip 33 having a pair of legs 34, 35which are biased inwardly toward each other and conneeted'at their upperends by a spring loop 36 so that they can be pulled apart for insertioninto adjacent holes' 30 in the-slabs forming a sleeve and when soengaged will tend to pull the slabs together.

Toiorrn a hot -top-usi1ig compression clips, the slabs 14, 15 areassembled and interlocked to form a sleeve; The slabs are lockedtogetherby inserting a 'compres sion' clip into adjacent holes 3i? at eachcorner oithe sleeve, and the "top is-mounted in the open mouth of Otherformsof hot top sleeves formed of a'plurality.

of slabs may be used in conneetio'n'withthe present invention, althoughthey have not been illustrated. For

example, slabs which are tapered from top to bottom may be used to forma sleeve having a tapered interior,

, that is, an interior wall surface whichtapers downwardly hot top. Forreceiving the legs 27, 28 of such clips, 7

, each of the slabs is provided at a point adjacent each end thereof,with a ventical hole 30 definedby ametal These pipes are positioned at apoint intermediate the wall surfaces of these slabs and adjacent eachendthereof but at 'a point inwardly of the interlocking tongues 18, 20and 21. The legs of the clip are slipped into the holes 30 of the slabswith one leg in the corner hole in one slab and the other leg in thecorner hole in an adjacent interlocking slab. The hair pinexpansion clip26 is formed from a bar of resilient steel so as to have suflicientspring strength to exert some force on the slabs and urge them apart. Toaccomplish this, the outwardly diverginglegs 27, 28 of the expansionclip 26 must be slightly comand outwardly; from a relatively narrowertop open ing, to awider bottom opening. Also, the sleeves can beelongated for use in slab molds, or can even be sub stantially circular.In the'last mentioned case, for example, a circular sleeve might beformed in two semicircular, or semiannular, parts, or possibly threeparts, for ease in shipment, and then assembled and inserted in a moldor hot top utilizing the expansion clips described above to hold thesleeve tightly against the mold walls.

With the expandable hot top construction described the danger of moltenmetal leaking between the hot top and mold walls is substantiallyeliminated because the hot top forming portions are held tightly againstthe mold '-walls. The hot top can'be shipped ma knocked down pressedorurged towards each other and then slipped into the holes. Itwill beappreciated, of course, that the legs mustdiverge to a greater extentthan the spacing between the holes 3% in adjacent interlocking slabs.

To mount ahot top embodying the invention in a mold, four slabs areassembled in an interlocking arrangement as. described above, and arelocked together by the insertion of the corner pins 16 through theinterlocking 16 prevent the expansion clips 30 from expandingthe. 7

hot top slabs. The hot top sleeve (FIG. v3) is then inserted into themouth of a mold 12 and is supported therein by bars 25- extendingbetween the I hooks 24 on a pair of opposed side slabs 15.

condition and assembled at the foundry prior to use. The expansiblenature thereof prevents damage to the top from misalinement' and furtherprevents the slabs from slipping once they aremounted in the molds.Moreover, the size of the slab is not critical as the hot top willexpand into contact with the mold walls. If desired, the crack oropening leftbetween the slabs when theyexpand towards the mold walls canbe quickly and V easily caulked or filled with ajsealing compound if soI The mounting operation is completed by withdrawing the corner pins 16so that the expansion clips, 30 can urge the slabs into contact with thewalls of the mold. 12. Because the clip tends to expand after beingpositioned in theholes, it will urge the slabs apart and" away from eachother into contact with the mold walls. The frictional effects betweenthe slabs and the mold walls will hold the slabsin this position duringthe casting of molten metal into the mold. This assures a tightifitbetween: the slabs and the mold walls, thereby preventing molten metalfrom leaking between the slabs and the mold Wall to forma fin on theingot.

desired. V V

I claim as myinventron:

1. For use in an ingot mold, a hot topjcomprising,

four slabs arranged to form .a'sleeve, the abutting ends of adjoiningpairslof said slabsincluding interlocking tongues, said slabs beingprovided'with longitudinal apertures extending downwardly. throughsubstantially the entire length of said slabs adjacent each abutting endthereof, and sprin'g -tensioned' spreader means having a pair ofoutwardly biased legs fitted within the opposed apertures at theabutting ends of each adjoining pair oi said slabs for urgingsaidslabsapart, the legs of said spreader means extending downwardly throughsubstantially the entire length of said slabs "so as to urge thelowermost portions ofsai d' slabs apart whereby when said hot top isinserted inthe mold at least thelowermost portions of. said slabs areforced tightlyagainst the mold walls.

2. For use in an ingot mold, a hot top comprising .four slabs arrangedto form a sleeve, the abutting ends of adjoining pairs ofs'aidslabsincluding interlocking gitudinal apertures extending downwardly throughsubstantially the entire length of said slabs and positioned at pointsintermediate the wall surfaces of the slabs and adjacent each endthereof at a point inwardly of the interlocking horizontal tongues, andspring-tensioned spreader means having a pair of outwardly biased legsfitted within the opposed apertures at the abutting ends of eachadjoining pair of said slabs for urging said slabs apart, the legs ofsaid spreader means extending downwardly through substantially theentire length of said slabs so as to urge the lowermost portions of saidslabs apart whereby when said hot top is inserted in the mold the sleeveis expanded tightly against the mold walls.

3. For use in an ingot mold, a hot top comprising four slabs arranged toform a sleeve, the abutting ends of adjoining pairs of said slabsincluding tongues interlocking horizontally with the first one of saidpair of slabs having a tongue extending therefrom in the plane of saidslab and the second one of said pair of slabs having a pair of spacedtongues extending therefrom in the plane of said second slab anddefining a slot for receiving the tongue on the first one of said pairof slabs, said slabs being provided with longitudinal aperturesextending downwardly through substantially the entire length of saidslabs adjacent each abutting end thereof, and a generally U-shapedspring-tensioned spreader having its outwardly biased legs fitted withinthe opposed apertures at the abutting ends of each adjoining pair or"said slabs for urging said slabs apart, the legs of said spreaderextending downwardly through substantially the entire length of saidslabs so as to urge the lowermost portions of said slabs apart wherebywhen said hot top is inserted in the mold the slabs are expanded tightlyagainst the mold walls.

References Cited in the file of this patent UNITED STATES PATENTS1,454,740 Howard et al May 8, 1923 1,892,464 Haws Dec. 27, 19322,301,101 Welshans Nov. 3, 1942 2,390,373 Jones et a1. Dec. 4, 19452,426,748 Rees et a1 Sept. 2, 1947 2,858,588 Hofiman Nov. 4, 19582,914,825 Marburg Dec. 1, 1959

1. FOR USE IN AN INGOT MOLD, A HOT TOP COMPRISING FOUR SLABS ARRANGED TOFORM A SLEEVE, THE ABUTTING ENDS OF ADJOINING PAIRS OF SAID SLABSINCLUDING INTERLOCKING TONGUES, SAID SLABS BEING PROVIDED WITHLONGTITUDINAL APERTURES EXTENDING DOWNWARDLY THROUGH SUBSTANTIALLY THEENTIRE LENGTH OF SAID SLABS ADJACENT EACH ABUTTING END THEREOF, ANDSPRING-TENSIONED SPREADER MEANS HAVING A PAIR OF OUTWARDLY BIASED LEGSFITTED WITHIN THE OPPOSED APERTURES AT THE ABUTTING ENDS OF EACHADJOINING PAIR OF SAID SLABS FOR URGING SAID SLABS APART, THE LEGS OFSAID SPREADER MEANS EXTENDING DOWNWARDLY THROUGH SUBSTANTIALLY THEENTIRE LENGTH OF SAID SLABS SO AS TO URGE THE LOWERMOST PORTIONS OF SAIDSLABS APART WHEREBY WHEN